I like the Nelson Rigg Spirit 10. Low profile, soft shell case, and surprisingly larger capacity than what I thought it would be. It does not need to be used in conjunction with the tank bra as pictured. Perhaps you're needing for bigger size due to camera, in which case, they have larger sizes as well.
For the GT there were two tank bag sizes, one "mini" and the other much larger. Both were coupled with tank bra. The "mini" is virtually impossible to get now unless you order JC's reproduction. The larger version is fairly rare as well but I see it on EBay every long while.